add mqtt and device test

talkingq-url/services/offline_audio_cache.py

@@ -25,7 +25,10 @@ class OfflineAudioCache:
     async def has_pending_audio(self, device_id: str) -> bool:
         async with self.lock:
             return device_id in self.offline_audio and len(self.offline_audio[device_id]) > 0
-
+    
+    async def get_all_audio_cache(self) -> List[str]:
+        async with self.lock:
+            return self.offline_audio
 
 # 单例实例
 offline_audio_cache = OfflineAudioCache()